Abstract: The present invention relates to a method of copy protecting optical discs, such as CDs or DVDs. Instead of encoding data onto the CD-ROMs in a conventional manner which ensures balanced dc content, for copy protection the digital data is encoded and recorded onto the optical disc such that it is arranged to give some of the recorded digital data highly unbalanced dc content. Thus, for example, the DSV (digital sum value) value of the encoded data is recorded so that the DSV value changes continuously once 50 frames of data or more.

Abstract: The more effective is the copy protection provided on a DVD, the greater is the likelihood that the copy protection will adversely interfere with legitimate uses of the disc. In a disc where the content is arranged in physical sectors, it is now proposed to provide subversive regions on the disc having a similar structure to genuine regions. A subversive region and a genuine region will each extend over one or more physical sectors. The subversive region will be provided with physical sector addresses which coincide with addresses of the genuine region. Navigational data will ensure that it is the genuine, rather than the subversive, region which will be accessed during normal play, but the subversive region will effectively hide the genuine region during copying.

Abstract: DVDs can be copy protected by incorporating regions which contain unreadable or subversive data within the data area (42). For example, such a region may be configured as a cell of a video object (VOB) (50) within a VOB file (51). Access to the region of subversive data is prevented during normal playback, for example, by ensuring that there are no pointers leading to the subversive region. To defeat such a copy protection method, the content on the copy protected optical disc is accessed by utilising the navigation provided for normal playback of the disc. Thus, the subversive regions are navigated around during copying of the disc. The accessed content is stored in a corresponding data area and, where subversive regions are identified, arbitrary data is incorporated within regions of the copy data area which correspond to regions of unreadable or subversive data in the original data area.

Abstract: A copy protection technique is described which enables the content (14) of an application file (4, 20), for example, provided by a licensed game provider, to be copy protected without action having to be taken at the time of encoding the application file onto a DVD or other optical disc. DSV data patterns, that is data patterns which are difficult to encode without causing DSV problems, are to be incorporated in the application file (4, 20). It is expected that sophisticated encoders (8) at games console manufacturers will be able, for example, by using look-ahead techniques, to encode and apply the application to the glass master (10) in a manner such that the encoded data will not cause DSV problems. However, if an attempt is made to read the data on the original disc, for example, for copying purposes, the DSV data patterns will cause a CD or DVD writer to encode the data onto the copy disc in a manner which renders the resultant copy disc effectively unplayable.

Abstract: The present invention relates to a method of copy protecting optical discs, such as CD-ROMs. Instead of encoding data onto the CD-ROMs in a manner which ensures balanced dc content, for copy protection the digital data is encoded and recorded onto the optical disc such that it is arranged to give some of the recorded digital data unbalanced dc content. Thus, for example, the DSV value of the encoded data may be changed rapidly in less than (100) frames to (FIG. 9). For an area of digital data on the optical disc in which the DSV has been caused to rise steeply (FIG. 10a), heavy distortions in audio arise (FIG. 10c) during an attempt to copy an audio track including the single segment of unbalanced dc content.

Abstract: A method of copy protecting optical discs uses the differences in capability between the encoder associated with a laser beam recorder and that in currently available CD writers. Digital sum value (DSV) is a property of the encoded data on CDs and an encoder, which controls a laser beam recorder may be able to choose a pattern of merge bits which result in the overall DSV having optimal properties. During mastering of a CD, data patterns are added to the disc to provide an authenticating signature. These data patterns are chosen to cause DSV problems. Currently available CD writers have been found to have difficulty writing an authenticating signature of the type described without producing a resulting CD which has severe readability problems. Thus, the copy disc written by the CD writer will result in a CD reader returning corrupted data or information signalling a read error.

Abstract: The more effective is the copy protection provided on a DVD, the greater is the likelihood that the copy protection will adversely interfere with legitimate uses of the disc. In a disc where the content is arranged in physical sectors, it is now proposed to provide subversive regions on the disc having a similar structure to genuine regions. A subversive region and a genuine region will each extend over one or more physical sectors. The subversive region will be provided with physical sector addresses which coincide with addresses of the genuine region. Navigational data will ensure that it is the genuine, rather than the subversive, region which will be accessed during normal play, but the subversive region will effectively hide the genuine region during copying.

Abstract: The method and apparatus described utilise the fact that CDs manufactured from the same master will have distinctive physical characteristics attributable to the physical manufacturing process of the master to distinguish counterfeit CDs from genuine discs. For a genuine disc, the relative angular orientation of specified sections of the recorded data are determined and recorded. The relative angular orientation of the same sections of data on a test disc are also determined. Where the relative angular orientations are the same it is concluded that the test disc derives from the same source as the genuine disc and is therefore bona fide. Where there is no correlation, the test disc may be identified as counterfeit. The relative angular orientations, or other physical characteristics of the discs, may be physically measured, or may be calculated from information gained by reading the data on the disc. The disclosed technique can also be used to copy protect discs.

Abstract: It is proposed to copy protect data files for transmission by incorporating DSV data patterns, that is, data patterns which are difficult to encode without causing DSV problems, in the data files. The data in five audio streams and two video streams is placed, by way of encoders (10) and a multiplexer (12) into a stream of blocks of encoded data in the MPEG file format (14). In this format, blocks of video data V are arranged alternately with blocks of audio data A and padding stream blocks P. DSV data patterns (16) are incorporated into the MPEG file (14) by way of an encoder (18) to produce the copy protected data file (15). The DSV data patterns (16) are incorporated into locations within the MPEG file which have no data content such as padding stream blocks P and/or into unused audio data blocks A.

Abstract: The method and apparatus described utilise the fact that CDs manufactured from the same master will have distinctive physical characteristics attributable to the physical manufacturing process of the master to distinguish counterfeit CDs from genuine discs. For a genuine disc, the relative angular orientation of specified sections of the recorded data are determined and recorded. The relative angular orientation of the same sections of data on a test disc are also determined. Where the relative angular orientations are the same it is concluded that the test disc derives from the same source as the genuine disc and is therefore bona fide. Where there is no correlation, the test disc may be identified as counterfeit. The relative angular orientations, or other physical characteristics of the discs, may be physically measured, or may be calculated from information gained by reading the data on the disc. The disclosed technique can also be used to copy protect discs.

Abstract: The method and apparatus described utilise the fact that CDs manufactured from the same master will have distinctive physical characteristics attributable to the physical manufacturing process of the master to distinguish counterfeit CDs from genuine discs. For a genuine disc, the relative angular orientation of specified sections of the recorded data are determined and recorded. The relative angular orientation of the same sections of data on a test disc are also determined. Where the relative angular orientations are the same it is concluded that the test disc derives from the same source as the genuine disc and is therefore bona fide. Where there is no correlation, the test disc may be identified as counterfeit. The relative angular orientations, or other physical characteristics of the discs, may be physically measured, or may be calculated from information gained by reading the data on the disc. The disclosed technique can also be used to copy protect discs.

Abstract: DVDs can be copy protected by incorporating regions which contain unreadable or subversive data within the data area (42). For example, such a region may be configured as a cell of a video object (VOB) (50) within a VOB file (51). Access to the region of subversive data is prevented during normal playback, for example, by ensuring that there are no pointers leading to the subversive region. To defeat such a copy protection method, the content on the copy protected optical disc is accessed by utilising the navigation provided for normal playback of the disc. Thus, the subversive regions are navigated around during copying of the disc. The accessed content is stored in a corresponding data area and, where subversive regions are identified, arbitrary data is incorporated within regions of the copy data area which correspond to regions of unreadable or subversive data in the original data area.

Abstract: The present invention relates to a method of copy protecting optical discs, such as CD-ROMs. Instead of encoding data onto the CD-ROMs in a manner which ensures balanced dc content, for copy protection the digital data is encoded and recorded onto the optical disc such that it is arranged to give some of the recorded digital data unbalanced dc content. Thus, for example, the DSV value of the encoded data may be changed rapidly in less than (100) frames to (FIG. 9). For an area of digital data on the optical disc in which the DSV has been caused to rise steeply (FIG. 10a), heavy distortions in audio arise (FIG. 10c) during an attempt to copy an audio track including the single segment of unbalanced dc content.

Abstract: It is proposed to copy protect data files for transmission by incorporating DSV data patterns, that is, data patterns which are difficult to encode without causing DSV problems, in the data files. The data in five audio streams and two video streams is placed, by way of encoders (10) and a multiplexer (12) into a stream of blocks of encoded data in the MPEG file format (14). In this format, blocks of video data V are arranged alternately with blocks of audio data A and padding stream blocks P. DSV data patterns (16) are incorporated into the MPEG file (14) by way of an encoder (18) to produce the copy protected data file (15). The DSV data patterns (16) are incorporated into locations within the MPEG file which have no data content such as padding stream blocks P and/or into unused audio data blocks A.

Abstract: The present invention relates to an application file to be carried on an optical disc and to a method of copy protecting an application, where the application is provided by an application file to be carried on an optical disc. The invention also extends to a copy protected optical disc carrying an application and to a storage device for use in a process of mastering optical discs.

Abstract: In a method of copy protecting an optical disc carrying information and control data, access to selected information is controlled by removing, corrupting, or otherwise rendering incorrect or inaccurate control data describing the selected information. For example, where an optical disc carries both a first, audio, session (30) and a second, data, session (40), the audio session (30) can be effectively hidden from a data reader by including control data in the data session which incorrectly identifies audio files as data files. In addition, or as an alternative, information in the files, directories, or descriptors of the volume of information making up a data session may be removed, corrupted or rendered incorrect to similarly prevent a data reader accessing the information.

Abstract: The ability of a data reader, such as a CD-ROM drive, to access, extract, or otherwise read the data on a digital audio compact disc provides a problem for the music industry. A user can use his CD-ROM drive to read the data from an audio disc into a computer file, and then that data can be copied. To provide copy protection, errors are deliberately introduced into the data on a CD, but these errors are of a type which are generally transparent to an audio player but which will interfere with the reading of the audio data by a data reader. According to the standards, the data on a CD is encoded into frames by EFM (eight to fourteen modulation). Each frame has sync data, sub-code bits providing control and display symbols, data bits and parity bits, and includes 24 bytes of data, which is audio data for a CD-DA. The standard requires that 98 such frames are grouped into a sector. To provide copy protection, each is provided with a non-standard number of frames, for example, has 99 rather than 98 frames.

Abstract: In a system for protecting encoded digital data, for example, on a digital audio compact disc (CD-DA), specific audio samples are altered to cause spikes which are audible as clicks if played. All of the codewords in the encoded data which contain those altered samples are then identified, and data in each codeword is changed such that on decoding, the codewords will be identified as uncorrectable. Thus, if the decoded data is played by an audio player, error flags are reliably set so that error concealment, such as interpolation, is invoked and the spikes are inaudible. However, a data reader will either pass the uncorrectable data unchanged or will attempt to correct it. Therefore if a copy of the audio data is made, the clicks will be audible on playback.

Abstract: Digital data which is to be encoded, for example, for application to a CD, is subjected to error correcting encoding and is arranged in codewords, with each codeword containing data bytes and parity values. To copy protect such encoded digital data, the values of the data in a number of the data bytes in a selected codeword are altered. For audio data, for example, the values of the data bytes are altered to be representative of an unusually large magnitude, or click. It is also arranged that the alterations to the values of the data bytes and the number of data bytes altered render the altered codeword uncorrectable. This means that on decoding, for example, in a CD player, the decoder flags the codewords as uncorrectable whereby the data is subjected to interpolation or other error concealment. The clicks are therefore not imposed on the audio as played. However, copies which are made from the copy protected encoded digital data will generally be degraded.

Abstract: The method and apparatus described utilise the fact that CDs manufactured from the same master will have distinctive physical characteristics attributable to the physical manufacturing process of the master to distinguish counterfeit CDs from genuine discs. For a genuine disc, the relative angular orientation of specified sections of the recorded data are determined and recorded. The relative angular orientation of the same sections of data on a test disc are also determined. Where the relative angular orientations are the same it is concluded that the test disc derives from the same source as the genuine disc and is therefore bona fide. Where there is no correlation, the test disc may be identified as counterfeit. The relative angular orientations, or other physical characteristics of the discs, may be physically measured, or may be calculated from information gained by reading the data on the disc. The disclosed technique can also be used to copy protect discs.